Nasal mask



FIG. 1 is a perspective view of the nasal mask;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof, the left sideelevational view being a mirror image thereto;

FIG. 4 is a back elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a perspective view thereof, the broken line showing is forillustrative purposes only and forms no part of the claimed design.

The ornamental design for a nasal mask, as shown and described.